J. R. Petta

Split-Gate Cavity Coupler for Silicon Circuit Quantum Electrodynamics

  1. F. Borjans,
  2. X. Croot,
  3. S. Putz,
  4. X. Mi,
  5. S. M. Quinn,
  6. A. Pan,
  7. J. Kerckhoff,
  8. E. J. Pritchett,
  9. C. A. Jackson,
  10. L. F. Edge,
  11. R. S. Ross,
  12. T. D. Ladd,
  13. M. G. Borselli,
  14. M. F. Gyure,
  15. and J. R. Petta
Coherent charge-photon and spin-photon coupling has recently been achieved in silicon double quantum dots (DQD). Here we demonstrate a versatile split-gate cavity-coupler that allows
more than one DQD to be coupled to the same microwave cavity. Measurements of the cavity transmission as a function of level detuning yield a charge cavity coupling rate gc/2π = 58 MHz, charge decoherence rate γc/2π = 36 MHz, and cavity decay rate κ/2π = 1.2 MHz. The charge cavity coupling rate is in good agreement with device simulations. Our coupling technique can be extended to enable simultaneous coupling of multiple DQDs to the same cavity mode, opening the door to long-range coupling of semiconductor qubits using microwave frequency photons.
arxiv pdf

Realizing a Circuit Analog of an Optomechanical System with Longitudinally Coupled Superconducting Resonators

  1. C. Eichler,
  2. and J. R. Petta
We realize a superconducting circuit analog of the generic cavity-optomechanical Hamiltonian by longitudinally coupling two superconducting resonators, which are an order of magnitude
different in frequency. We achieve longitudinal coupling by embedding a superconducting quantum interference device (SQUID) into a high frequency resonator, making its resonance frequency depend on the zero point current fluctuations of a nearby low frequency LC-resonator. By employing sideband drive fields we enhance the intrinsic coupling strength of about 15 kHz up to 280 kHz by controlling the amplitude of the drive field. Our results pave the way towards the exploration of optomechanical effects in a fully superconducting platform and could enable quantum optics experiments with photons in the yet unexplored radio frequency band.
arxiv pdf

Circuit Quantum Electrodynamics Architecture for Gate-Defined Quantum Dots in Silicon

  1. X. Mi,
  2. J. V. Cady,
  3. D. M. Zajac,
  4. J. Stehlik,
  5. L. F. Edge,
  6. and J. R. Petta
We demonstrate a hybrid device architecture where the charge states in a double quantum dot (DQD) formed in a Si/SiGe heterostructure are read out using an on-chip superconducting microwave
cavity. A quality factor Q = 5,400 is achieved by selectively etching away regions of the quantum well and by reducing photon losses through low-pass filtering of the gate bias lines. Homodyne measurements of the cavity transmission reveal DQD charge stability diagrams. These measurements indicate that electrons trapped in a Si DQD can be effectively coupled to microwave photons, potentially enabling coherent electron-photon interactions in silicon.
arxiv pdf